The present invention relates to wheel hub assemblies, and more particularly to a grease retainer which provides for a reduced grease fill.
Wheel bearings have three central components, the rollers, bearing cone, and the bearing cup. The rollers are contained between the bearing cone and the bearing cup. The cone rests against a shaft spindle and the cup rests against the wheel hub. Grease retainers are typically installed such that the end portions are pressed between the wheel hub and bearing cups. The wheel hubs must be machined on the surface below the bearing cups to provide a proper mating surface for the grease retainer.
Known grease retainers require multiple components. Typically, a grease retainer is required for each bearing. Each grease retainer has an end portion and a side portion extending from the end portion. The end portion is pressed between the bearing cup and the wheel hub. The side portions of the retainers extend away from the bearing to form an area next to the bearings which is filled with grease. A similar retainer is installed for the second bearing. Disadvantageously, a gap may be formed between the retainers which may allow grease to pass into a cavity within the wheel hub. Although the grease retainers slow the movement of grease away from the bearings the retainers may not completely prevent such movement. To compensate for the gradual loss of grease, a rather large fill is typically provided.
Moreover, mounting the bearing cups upon the grease retainer may result in shifting of the bearings. A precise machine operation is therefore required to assure a proper mating surface for the grease retainer. This machining process requires additional time and expense.
Accordingly, it is desirable to provide a retainer which provides for a lower grease fill and the minimization of wheel hub machining.
A hub assembly according to the present invention includes a wheel hub mounted on a spindle. The hub assembly is assembled such that a grease retainer is installed in the hub, followed by a first bearing and a seal. The hub is then installed on the spindle, followed by a second bearing. Each wheel bearing has rollers, a bearing cone, and a bearing cup. The grease retainer is of a single piece which allows for a lower grease fill in the area adjacent the bearings. Installation of the retainer abutting the bearing cups eliminates machining of the wheel hubs otherwise required by other retainer designs.
The grease retainer extends between and is in engagement with the first and second bearing cups. The grease retainer is manufactured of a resilient material and has a generally cylindrical shape. A center portion of the grease retainer is generally parallel to its end portions. The center portion is radially offset from the end portions to reduce the required grease fill and prevent leakage of the grease past the retainer. The grease may be retained in the grease retainer prior to installation by a thin synthetic film that will rupture upon installation.
The present invention therefore provides a grease retainer which reduces the grease fill and minimizes machining of the wheel hubs.